AP Physics C: Mechanics Describing Motion I

Motion, or kinematics, is one of the most basic yet most useful sections in all of mechanics; you will take what you learn here and apply it to countless problems in the mechanics world. Here, we discuss the elements you’ll deal with in kinematic problems, such as the velocity vector, speed, and acceleration. Combined with mass, these are the backbone elements of mechanics. A bit of warning beforehand is to be aware of units! Unless otherwise stated, you should deal with kilograms (kg) for mass, meters (m) for displacement, and seconds (s) for time. These are the most universally used units in all of physics, so it’s important to remember what they are. Next, we’ll continue our discussion on kinematics in greater detail.

For 3.5Q on the AP Physics C Companion: Mechanics book, I think you meant t=1s and t=6s, not t=1s and t=5s, unless I am misreading. I didn't know where else to post this. Thanks!

1 answer

Last reply by: Professor Dan FullertonTue Dec 1, 2015 8:25 AM

Post by Jim Tangon November 30, 2015

In Example 7, Q2, how come you took "distance traveled" to mean displacement, even though it's understood somewhat. I thought we were supposed to distinguish between them, as you pointed out earlier in the lecture.

1 answer

Last reply by: Jesse LeflerWed Sep 9, 2015 6:11 AM

Post by David Schalleron September 8, 2015

At 19:24 why is it 2tcubed over three? I don't quite follow.

1 answer

Last reply by: Professor Dan FullertonMon Sep 7, 2015 5:09 PM

Post by Shehryar Khursheedon September 7, 2015

Where are the practice problems at the end of the lesson? That is, problems that I can do individually rather than you going over it in the lectures.

1 answer

Last reply by: Professor Dan FullertonThu May 7, 2015 5:47 AM

Post by Joshua Bowenon May 6, 2015

Hey i can not see the lecture it says error 2302

1 answer

Last reply by: SH LSun Mar 15, 2015 11:40 AM

Post by Lily Lauon March 15, 2015

At 12:19 for instantaneous velocity. Should the graph have the axis with respect to V instead of X ?

1 answer

Last reply by: Professor Dan FullertonSat Mar 14, 2015 11:43 AM

Post by Hlulani Rikhotsoon March 14, 2015

where can i get ap physics c past question papers

1 answer

Last reply by: Professor Dan FullertonThu Jan 8, 2015 12:46 PM

Post by Isaac Martinezon January 8, 2015

Download lectures?

1 answer

Last reply by: Professor Dan FullertonSat Dec 27, 2014 12:39 PM

Post by Jaime De Vizcarraon December 27, 2014

In the example VII: Tortoise and Hare, shouldn't the acceleration of the hare at 40s be a negative value since it is decelerating? {(2.5(m/s)-8(m/s)}/(40s)= -0.1375 m/s^2

1 answer

Last reply by: Professor Dan FullertonSun Dec 7, 2014 3:12 PM

Post by Dawud Muhammadon December 4, 2014

hey professor,other than these vids, what else can i do to sharpen my skills..??

Related Articles:

Describing Motion I

The vector from the origin to the object’s position is the position vector, r.

The change in an object’s position is called displacement.

Velocity is the time rate of change of displacement: v=dx/dt.

Acceleration is the time rate of change of velocity: a=dv/dt.

The slope of the position-time graph is the velocity. The slope of the velocity-time graph is the acceleration.

The area under the acceleration-time graph gives you change in velocity. The area under the velocity-time graph gives you change in position.

For cases of constant acceleration, you can utilize the kinematic equations to solve for unknown quantities.

Objects under the force of gravity only are said to be in free fall.

The acceleration due to gravity on the surface of Earth is 9.8 meters per second per second toward the center of the Earth.

Describing Motion I

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

Related Books

This book includes a comprehensive review of the key AP Physics C concepts and targeted strategies for acing every section of the exam. Additionally, the book includes two full length practice tests with full answer explanations.

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